﻿//===============================================================================
// Microsoft patterns & practices Enterprise Library
// Core
//===============================================================================
// Copyright © Microsoft Corporation.  All rights reserved.
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY
// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT
// LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
// FITNESS FOR A PARTICULAR PURPOSE.
//===============================================================================

using System;
using System.Collections.Generic;
using System.IO;
using Microsoft.Practices.EnterpriseLibrary.Common.Configuration.Manageability.Properties;

namespace Microsoft.Practices.EnterpriseLibrary.Common.Configuration.Manageability
{
	/// <summary>
	/// Manages the singleton <see cref="ManageableConfigurationSourceImplementation"/> instance for a given 
	/// file name, application name and group policy enablement combination.
	/// </summary>
	public class ManageableConfigurationSourceSingletonHelper : IDisposable
	{
		private readonly IDictionary<ImplementationKey, ManageableConfigurationSourceImplementation> instances;
		private readonly object lockObject = new object();
		internal bool refresh;

		/// <summary>
		/// Initialzie a new instance of the <see cref="ManageableConfigurationSourceSingletonHelper"/> class.
		/// </summary>
		public ManageableConfigurationSourceSingletonHelper()
			: this(true)
		{
		}

		/// <summary>
		/// Initialize a new instace of the <see cref="ManageableConfigurationSourceSingletonHelper"/> class.
		/// </summary>
		/// <param name="refresh">
		/// true to support refreshing; otherwise, false.
		/// </param>
		public ManageableConfigurationSourceSingletonHelper(bool refresh)
		{
			this.refresh = refresh;
			instances
				= new Dictionary<ImplementationKey, ManageableConfigurationSourceImplementation>(new ImplementationKeyComparer());
		}

		///<summary>
		/// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
		///</summary>
		public void Dispose()
		{
			foreach (ManageableConfigurationSourceImplementation instance in instances.Values)
			{
				instance.Dispose();
			}
		}

		/// <summary>
		/// Gets a <see cref="ManageableConfigurationSourceImplementation"/> for a configuration.
		/// </summary>
		/// <param name="configurationFilePath">The path to a configuration file.</param>
		/// <param name="manageabilityProviders">The list of managment providers.</param>
		/// <param name="readGroupPolicies">true to read group policies; otherwise, false.</param>
		/// <param name="generateWmiObjects">true to generate wmi objects; otherwise, false.</param>
		/// <param name="applicationName">The name of the application.</param>
		/// <returns>A <see cref="ManageableConfigurationSourceImplementation"/> object.</returns>
		public ManageableConfigurationSourceImplementation GetInstance(String configurationFilePath,
		                                                               IDictionary
		                                                               	<String, ConfigurationSectionManageabilityProvider>
		                                                               	manageabilityProviders,
		                                                               bool readGroupPolicies,
		                                                               bool generateWmiObjects,
		                                                               String applicationName)
		{
			if (String.IsNullOrEmpty(configurationFilePath))
				throw new ArgumentException(Resources.ExceptionStringNullOrEmpty, "configurationFilePath");

			String rootedConfigurationFilePath = RootConfigurationFilePath(configurationFilePath);

			if (!File.Exists(rootedConfigurationFilePath))
				throw new FileNotFoundException(
					String.Format(Resources.Culture, Resources.ExceptionConfigurationLoadFileNotFound, rootedConfigurationFilePath));

			ImplementationKey key = new ImplementationKey(rootedConfigurationFilePath, applicationName, readGroupPolicies);
			ManageableConfigurationSourceImplementation instance;

			lock (lockObject)
			{
				instances.TryGetValue(key, out instance);
				if (instance == null)
				{
					instance = new ManageableConfigurationSourceImplementation(rootedConfigurationFilePath,
					                                                           refresh,
					                                                           manageabilityProviders,
					                                                           readGroupPolicies,
					                                                           generateWmiObjects,
					                                                           applicationName);
					instances.Add(key, instance);
				}
			}

			return instance;
		}

		private static String RootConfigurationFilePath(String configurationFilePath)
		{
			String rootedConfigurationFile = configurationFilePath;
			if (!Path.IsPathRooted(rootedConfigurationFile))
			{
				rootedConfigurationFile
					= Path.GetFullPath(Path.Combine(AppDomain.CurrentDomain.BaseDirectory, rootedConfigurationFile));
			}
			return rootedConfigurationFile;
		}
	}
}
